# def func(a, b):
#     try:
#         print(a + b)
#         print(a / b)
#         print(a - b)
#     except ZeroDivisionError:
#         print('try中出现异常')


# func(1, 0)

# try:
#     print(x)
# except:
#     print('没有x')
# else:
#     print('有没有x我都会输出')
# print('ending...')

# 函数中的默认参数在定义函数时
def div(a,b):
    